go-xmpp/client.go

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package xmpp
import (
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"context"
"encoding/xml"
"errors"
"io"
"net"
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"sync"
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"time"
"gosrc.io/xmpp/stanza"
)
//=============================================================================
// EventManager
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// SyncConnState represents the current connection state.
type SyncConnState struct {
sync.RWMutex
// Current state of the client. Please use the dedicated getter and setter for this field as they are thread safe.
state ConnState
}
type ConnState = uint8
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// getState is a thread-safe getter for the current state
func (scs *SyncConnState) getState() ConnState {
var res ConnState
scs.RLock()
res = scs.state
scs.RUnlock()
return res
}
// setState is a thread-safe setter for the current
func (scs *SyncConnState) setState(cs ConnState) {
scs.Lock()
scs.state = cs
scs.Unlock()
}
// This is a the list of events happening on the connection that the
// client can be notified about.
const (
StateDisconnected ConnState = iota
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StateResuming
StateSessionEstablished
StateStreamError
StatePermanentError
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InitialPresence = "<presence/>"
)
// Event is a structure use to convey event changes related to client state. This
// is for example used to notify the client when the client get disconnected.
type Event struct {
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State SyncConnState
Description string
StreamError string
SMState SMState
}
// SMState holds Stream Management information regarding the session that can be
// used to resume session after disconnect
type SMState struct {
// Stream Management ID
Id string
// Inbound stanza count
Inbound uint
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// IP affinity
preferredReconAddr string
// Error
StreamErrorGroup stanza.StanzaErrorGroup
// Track sent stanzas
*stanza.UnAckQueue
// TODO Store max and timestamp, to check if we should retry resumption or not
}
// EventHandler is use to pass events about state of the connection to
// client implementation.
type EventHandler func(Event) error
type EventManager struct {
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// Store current state. Please use "getState" and "setState" to access and/or modify this.
CurrentState SyncConnState
// Callback used to propagate connection state changes
Handler EventHandler
}
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// updateState changes the CurrentState in the event manager. The state read is threadsafe but there is no guarantee
// regarding the triggered callback function.
func (em *EventManager) updateState(state ConnState) {
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em.CurrentState.setState(state)
if em.Handler != nil {
em.Handler(Event{State: em.CurrentState})
}
}
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// disconnected changes the CurrentState in the event manager to "disconnected". The state read is threadsafe but there is no guarantee
// regarding the triggered callback function.
func (em *EventManager) disconnected(state SMState) {
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em.CurrentState.setState(StateDisconnected)
if em.Handler != nil {
em.Handler(Event{State: em.CurrentState, SMState: state})
}
}
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// streamError changes the CurrentState in the event manager to "streamError". The state read is threadsafe but there is no guarantee
// regarding the triggered callback function.
func (em *EventManager) streamError(error, desc string) {
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em.CurrentState.setState(StateStreamError)
if em.Handler != nil {
em.Handler(Event{State: em.CurrentState, StreamError: error, Description: desc})
}
}
// Client
// ============================================================================
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var ErrCanOnlySendGetOrSetIq = errors.New("SendIQ can only send get and set IQ stanzas")
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// Client is the main structure used to connect as a client on an XMPP
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// server.
type Client struct {
// Store user defined options and states
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config *Config
// Session gather data that can be accessed by users of this library
Session *Session
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transport Transport
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// Router is used to dispatch packets
router *Router
// Track and broadcast connection state
EventManager
// Handle errors from client execution
ErrorHandler func(error)
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// Post connection hook. This will be executed on first connection
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PostConnectHook func() error
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// Post resume hook. This will be executed after the client resumes a lost connection using StreamManagement (XEP-0198)
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PostResumeHook func() error
}
/*
Setting up the client / Checking the parameters
*/
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// NewClient generates a new XMPP client, based on Config passed as parameters.
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// If host is not specified, the DNS SRV should be used to find the host from the domain part of the Jid.
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// Default the port to 5222.
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func NewClient(config *Config, r *Router, errorHandler func(error)) (c *Client, err error) {
if config.KeepaliveInterval == 0 {
config.KeepaliveInterval = time.Second * 30
}
// Parse Jid
if config.parsedJid, err = stanza.NewJid(config.Jid); err != nil {
err = errors.New("missing jid")
return nil, NewConnError(err, true)
}
if config.Credential.secret == "" {
err = errors.New("missing credential")
return nil, NewConnError(err, true)
}
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// Fallback to jid domain
if config.Address == "" {
config.Address = config.parsedJid.Domain
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// Fetch SRV DNS-Entries
_, srvEntries, err := net.LookupSRV("xmpp-client", "tcp", config.parsedJid.Domain)
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if err == nil && len(srvEntries) > 0 {
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// If we found matching DNS records, use the entry with highest weight
bestSrv := srvEntries[0]
for _, srv := range srvEntries {
if srv.Priority <= bestSrv.Priority && srv.Weight >= bestSrv.Weight {
bestSrv = srv
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config.Address = ensurePort(srv.Target, int(srv.Port))
}
}
}
}
if config.Domain == "" {
// Fallback to jid domain
config.Domain = config.parsedJid.Domain
}
c = new(Client)
c.config = config
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c.router = r
c.ErrorHandler = errorHandler
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if c.config.ConnectTimeout == 0 {
c.config.ConnectTimeout = 15 // 15 second as default
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}
if config.TransportConfiguration.Domain == "" {
config.TransportConfiguration.Domain = config.parsedJid.Domain
}
c.config.TransportConfiguration.ConnectTimeout = c.config.ConnectTimeout
c.transport = NewClientTransport(c.config.TransportConfiguration)
if config.StreamLogger != nil {
c.transport.LogTraffic(config.StreamLogger)
}
return
}
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// Connect establishes a first time connection to a XMPP server.
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// It calls the PostConnectHook
func (c *Client) Connect() error {
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err := c.connect()
if err != nil {
return err
}
// TODO: Do we always want to send initial presence automatically ?
// Do we need an option to avoid that or do we rely on client to send the presence itself ?
err = c.sendWithWriter(c.transport, []byte(InitialPresence))
// Execute the post first connection hook. Typically this holds "ask for roster" and this type of actions.
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if c.PostConnectHook != nil {
err = c.PostConnectHook()
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if err != nil {
return err
}
}
// Start the keepalive go routine
keepaliveQuit := make(chan struct{})
go keepalive(c.transport, c.config.KeepaliveInterval, keepaliveQuit)
// Start the receiver go routine
go c.recv(keepaliveQuit)
return err
}
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// connect establishes an actual TCP connection, based on previously defined parameters, as well as a XMPP session
func (c *Client) connect() error {
var state SMState
var err error
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// This is the TCP connection
streamId, err := c.transport.Connect()
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if err != nil {
return err
}
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// Client is ok, we now open XMPP session with TLS negotiation if possible and session resume or binding
// depending on state.
if c.Session, err = NewSession(c, state); err != nil {
// Try to get the stream close tag from the server.
go func() {
for {
val, err := stanza.NextPacket(c.transport.GetDecoder())
if err != nil {
c.ErrorHandler(err)
c.disconnected(state)
return
}
switch val.(type) {
case stanza.StreamClosePacket:
// TCP messages should arrive in order, so we can expect to get nothing more after this occurs
c.transport.ReceivedStreamClose()
return
}
}
}()
c.Disconnect()
return err
}
c.Session.StreamId = streamId
c.updateState(StateSessionEstablished)
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return err
}
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// Resume attempts resuming a Stream Managed session, based on the provided stream management
// state. See XEP-0198
func (c *Client) Resume() error {
c.EventManager.updateState(StateResuming)
err := c.connect()
if err != nil {
return err
}
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// Execute post reconnect hook. This can be different from the first connection hook, and not trigger roster retrieval
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// for example.
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if c.PostResumeHook != nil {
err = c.PostResumeHook()
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}
return err
}
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// Disconnect disconnects the client from the server, sending a stream close nonza and closing the TCP connection.
func (c *Client) Disconnect() error {
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if c.transport != nil {
return c.transport.Close()
}
// No transport so no connection.
return nil
}
func (c *Client) SetHandler(handler EventHandler) {
c.Handler = handler
}
// Send marshals XMPP stanza and sends it to the server.
func (c *Client) Send(packet stanza.Packet) error {
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conn := c.transport
if conn == nil {
return errors.New("client is not connected")
}
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data, err := xml.Marshal(packet)
if err != nil {
return errors.New("cannot marshal packet " + err.Error())
}
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// Store stanza as non-acked as part of stream management
// See https://xmpp.org/extensions/xep-0198.html#scenarios
if c.config.StreamManagementEnable {
if _, ok := packet.(stanza.SMRequest); !ok {
toStore := stanza.UnAckedStz{Stz: string(data)}
c.Session.SMState.UnAckQueue.Push(&toStore)
}
}
return c.sendWithWriter(c.transport, data)
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}
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// SendIQ sends an IQ set or get stanza to the server. If a result is received
// the provided handler function will automatically be called.
//
// The provided context should have a timeout to prevent the client from waiting
// forever for an IQ result. For example:
//
// ctx, _ := context.WithTimeout(context.Background(), 30 * time.Second)
// result := <- client.SendIQ(ctx, iq)
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//
func (c *Client) SendIQ(ctx context.Context, iq *stanza.IQ) (chan stanza.IQ, error) {
if iq.Attrs.Type != stanza.IQTypeSet && iq.Attrs.Type != stanza.IQTypeGet {
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return nil, ErrCanOnlySendGetOrSetIq
}
if err := c.Send(iq); err != nil {
return nil, err
}
return c.router.NewIQResultRoute(ctx, iq.Attrs.Id), nil
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}
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// SendRaw sends an XMPP stanza as a string to the server.
// It can be invalid XML or XMPP content. In that case, the server will
// disconnect the client. It is up to the user of this method to
// carefully craft the XML content to produce valid XMPP.
func (c *Client) SendRaw(packet string) error {
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conn := c.transport
if conn == nil {
return errors.New("client is not connected")
}
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// Store stanza as non-acked as part of stream management
// See https://xmpp.org/extensions/xep-0198.html#scenarios
if c.config.StreamManagementEnable {
toStore := stanza.UnAckedStz{Stz: packet}
c.Session.SMState.UnAckQueue.Push(&toStore)
}
return c.sendWithWriter(c.transport, []byte(packet))
}
func (c *Client) sendWithWriter(writer io.Writer, packet []byte) error {
var err error
_, err = writer.Write(packet)
return err
}
// ============================================================================
// Go routines
// Loop: Receive data from server
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func (c *Client) recv(keepaliveQuit chan<- struct{}) {
defer close(keepaliveQuit)
for {
val, err := stanza.NextPacket(c.transport.GetDecoder())
if err != nil {
c.ErrorHandler(err)
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c.disconnected(c.Session.SMState)
return
}
// Handle stream errors
switch packet := val.(type) {
case stanza.StreamError:
c.router.route(c, val)
c.streamError(packet.Error.Local, packet.Text)
c.ErrorHandler(errors.New("stream error: " + packet.Error.Local))
// We don't return here, because we want to wait for the stream close tag from the server, or timeout.
c.Disconnect()
// Process Stream management nonzas
case stanza.SMRequest:
answer := stanza.SMAnswer{XMLName: xml.Name{
Space: stanza.NSStreamManagement,
Local: "a",
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}, H: c.Session.SMState.Inbound}
err = c.Send(answer)
if err != nil {
c.ErrorHandler(err)
return
}
case stanza.StreamClosePacket:
// TCP messages should arrive in order, so we can expect to get nothing more after this occurs
c.transport.ReceivedStreamClose()
return
default:
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c.Session.SMState.Inbound++
}
// Do normal route processing in a go-routine so we can immediately
// start receiving other stanzas. This also allows route handlers to
// send and receive more stanzas.
go c.router.route(c, val)
}
}
// Loop: send whitespace keepalive to server
// This is use to keep the connection open, but also to detect connection loss
// and trigger proper client connection shutdown.
func keepalive(transport Transport, interval time.Duration, quit <-chan struct{}) {
ticker := time.NewTicker(interval)
for {
select {
case <-ticker.C:
if err := transport.Ping(); err != nil {
// When keepalive fails, we force close the transport. In all cases, the recv will also fail.
ticker.Stop()
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_ = transport.Close()
return
}
case <-quit:
ticker.Stop()
return
}
}
}